System and method of communication



Jan. 30, 1951 RlNEs 2,539,476

SYSTEM AND METHOD OF COMIUNICATI ON Filed June 23, 1943 I 6'9 E4512 5a 1 Patented Jan. 30, I951 UNITED STATES PATENT OFFICE SYSTEM AND METHOD OF COMMUNICATION Robert-Harvey Rines, Brnokline, Mass.

Application June 23, 1943, Serial No. 492,167

35 Claims.

The present" invention relates to system and methods of communication, and more particularly to the generation, transmission and reception in radio.

An object of the invention is to provide a new and" improved system and method for the modulation and demodulation of radio waves.

A further object is to provide a novel system and method for mechanically modulating radio waves.

Another object is to provide a new and improvedsystem and method for modulating reflected radio waves.

Other and further objects will be explained hereinafterand will be particularly pointed out in the appended claims.

The invention will-now be more fully explained in connection with the accompanying drawings, in which Fig. l is a diagrammatic view of circuits and apparatus illustrating the transmission and reception of waves modulated piezoelectrically in accordance with the present invention; Fig. 2 is a similar diagram illustrating magnetostrictive modulation; Fig. 3 is a similar diagram illustrating modulation eflected with the aid ofa tuning i'oi'lc: Fig. 4 is a similar diagram illustrating modulation produced with the aid'of a resonating air column; Fig. 5' is a similar diagram illustrating the modulation of a reflected radio wave; and Fig. 6 is a similar diagram 11- lustrating the modulation of high-frequency waves.

Referring first to Fig. 1, the two elements or a linear dipole'antenna are shown at 2 and l. The

antenna 2-1 is of the type that emits radio waves into space in response to electrical excitation by radio-frequency energy drawn by the antenna from a radio-frequency-energy-generatlng electric system prior to the emission of the'radio-irequency energy as radio waves. Antcnnas of" this type need not take the specific form of a diplole, but may have other forms including, for example; the single elements of'Figs. 2 and 3. The particular antenna 2-4 is shown oriented'verticallyto emit a bundle of ray oi radio wave in widely separated directions, being omni-directional'in the horizontal pianeand directional in the vertical plane, there being no end on radiation. A radio-frequency generator 8 may constitute the radio-frequency-energygeneratingelectric system or source of radiofrequcncyenergy connected to the antenna 2=4 by a transmission line in order that the antenna may become enabled to draw radio-frequency 2 energy from the electric system, thereby to'produce radio waves, emitting the radio waves into space as above described.

A mechanically vibratory member comprising, for example, a piezoelectric crystal 8, is shown mounted with its conducting electrode elements Ill and I 2' spaced from, but close to, the adjacent ends oi'the dipole elements 2 and l to which they are therefore electromagnetically coupled. Dielectric or insulating members It and it are shown spacing the crystal electrode members l0 and l 2" from the adjacent ends of the respective antenna elements 2 and 4. The crystal 8 may be vibrated by connecting its electrodes i0 and I2 to a source oi vibrational energy such a a beat-frequency or a signal audio oscillator ll.

, The vibrations thus produced in the piezoelectric crystal 8 will be transmitted through the electrodes l0 and I2 and the insulating elements H and I8 to the dipole elements 2 and t in a direction at an angle to all thedirections in which radio waves are emitted and at right angles to the horizontal radio-wave field pattern. This results in varying the dimension oithe dipole antenna elements at frequencie dependent upon the frequency of the vibrations of the piezoelectric crystal 8. As the crystal 8 vibrates, moreover, thespacing and coupling between the electrodes l0 and I2 and the respective dipole elements 2 and 4 are periodically varied in response to the vibration of the crystal 8. These dimensional variations in the physical, and hence in the eflective electrical dimensions or impedance oitheantenna; have been found to produce-corresponding. variations in the radio -frequency-energy drawn from the generating electric system 8,.thereby toeflect modulation ofthe electromagnetic radio waves emitted by the antenna 2-4;

The modulated electric waves will be received at a receiving stationin any desired way; as by means of a similar dipole the two elements of which are shown: at- 20' and 22', adapted to: be

tenna 50-52 and re-radiates the waves. dimensions of the element 58 may be varied in any desired way, as by means of a piezoelectric crystal 58, excited from an audio osthat one element only would, of course, then become modulated. The degree of the modulation will depend upon the position of the piezo-electric crystal with respect to the dipole element 2 or 4. It was found, for the case of a hollow half-wave dipole, that the best results were obtained with the crystal at either end of the corresponding dipole element, but in all cases the before-described modulation effects were discernible, the mechanical vibration of the high-frequency-current-supporting elements producing current alternations therein of the same periodioity as the mechanical vibrations.

The dimensional variations of the antenna may be produced by other means than by vibrating with a piezoelectric crystal. According, for example, to the modification of Fig. 2, an antenna 28, shown excited or fed through a transformer 30 from the generator 6, is constituted of mag- .netostrictive material. It is shown enclosed in magnetostrictive windings 32 and 34 of a magnetostrictive oscillator of the Pierce type, the vacuum tube of which is shown at 38. The length and other dimensions of the antenna 28, theretors, are varied during the generation of the radio waves, in order to modulate the waves.

- As illustrated in Fig. 3, the dimensions of the antenna 38, excited to produce radio waves as in Fig. 2, may be varied by means of a tuning fork 40 to effect themodulation of the radio waves. The dimensions of the antenna 38 are varied as the conducting tuning fork element, coupled thereto, vibrates towards and away from the end 'of the antenna 38. The tuning fork may be replaced by a vibrating bell or other mechanically vibrating member, including a diaphragm.

According to the modification shown in Fig.

'4, the antenna 42, excited to produce radio waves from a generator 48, is constituted of the outer surface of the tone arm oi a talking machine the needle 44 of which is shown riding over a record 46. The sound resonating in the tone arm 42 illustrated in Figs. 5 and 6. The radio waves produced by a driven dipole 50, 52, Fig. 5, as it draws radio-frequency energy from a generator 54 may excite and thus be reflected by a parasitic antenna element 56, as it intercepts at least part of the radio waves emitted by the dipole an- The cillator B0. The radio waves received and re-radiatcd by the parasitic element 55 will be'found to have become modulated as a result of the length and other dimensional variations 'of the element 56. A similar linear director parasitic antenna 82, excited by and supporting radio-frequency radiation from the driven elements .50, 52 may also be subjected to similar dimensional variations, as by means of a crystal 59, to

modulate the forward radiation of the driven elements 50, 52. and to reenforce the modulation .of the reflection on the reflector element 56.

63, excited electromagnetically by a generator 15 from which it draws radio-frequency energy to emit the energy as radio waves, and of a parasitic reflecting element 85, by means of crystals 61 4 and 59, respecti 'cly. The crystals 61 and 69 are synchronously excited by an audio-oscillator II to modulate the electromagnetic radiation reflected in a directional beam into space by rparabolic reflector 13.

The invention may be applied to other uses also. The production of a supersonically modulated radio wave may, for example, prove to be useful for conveying hidden information.

Further modifications will occur to persons skilled in the art and all such are considered to fall within the spirit and scope of the invention as defined in the appended claims.

What is claimed is:

1. An electromagnetic system having, in combination, an antenna, means for exciting the antenna to produce electromagnetic waves, and means for varying the length of the antenna to modulate the waves. -2. An electromagnetic system having, in combination, an antenna, means for exciting the antenna. to produce electromagnetic waves, and piezo-electric means for mechanically varying the length of the antenna to modulate the waves.

3. An electromagnetic system having, in combination, an antenna, means for exciting the antenna to produce electromagnetic waves, and magnetostrictive means for mechanically varying the length of the antenna to modulate the waves.

4. An electromagnetic system having, in combination, an antenna having conducting outer and inner surfaces, means for exciting the .outer surface of the antenna to produce electromagnetic waves, and means for mechanically resonating the antenna to modulate the waves.

5. An electromagnetic system having, in combination, an antenna, means for exciting the antenna electrically to produce electromagnetic waves, and means for vary e a dimension oi the antenna at an audio frequency to modulate the waves.

6. An electromagnetic system having, in combination, an antenna, means for exciting the antenna electrically to produce electromagnetic waves, and means for varying a dimension of the .antenna at supersonic frequency to modulate the waves.

7. A method of modulating electromagnetic waves produced from an electromagnetic-wave emitter of the type that draws electromagnetic energy from an electromagnetic-energy-generating electric system prior to the production from the electromagnetic energy of electromagnetic waves, that comprises varying a dimension of the emitter during the production of the electromagnetic waves and reflecting the modulated waves.

8. A method of modulating the radio waves emitted by an electromagnetic-wave antenna in widely separated directions in response to electrical excitation by the electromagnetic energy drawn by the antenna from an electromagneticenergy-generating electric system prior to the emission of the electromagnetic energy as electromagnetic waves, that comprises mechanically vibrating the antenna during the emission of the waves.

9. A method of modulating the radio waves emitted by a radio-wave antenna in a predetermined directlon in response to electrical excitation by radio-frequency energy drawn by the antenna from a radio-frequency-energy-generating electric system prior to the emission of the radiofrequency energy as radio waves, that comprises sumac mechanically vibrating the antenna-air an angle to -the said direction;

10. method of modulating-the radio'wavesemitted by a radio-wave antenna; in. a predetermined: directionin response toelectrical: excita-- tion by radio-frequenoy'energy d'rawabythe an tenna from a radio-firequency-energy generating electric-system prior to'theemissibmotthe radio;- f-requency energy as' radio waves-that comprises mechanically vibratingthe antenna. at right angles to the saidfiirection.

11. A radio transmitter having, in: combinat- I tion; an antennaof thetypethat emits: radio waves into space in response-to electricaliexcitae tlon by" radio-frequency energy drawn: byv' the antenna from a-radio-frequenoy-energy generat ing electric' systerm prior to the: emission-oithe radio-frequency energy as radio waves; an:- electric system'- for generating radio-frequency ener yt means 'electrica-lly' connecting the antenna to' the electric systemin order that the antenna may draw radio-frequency energy from-theelmtric system, thereby to cause the ant'enna tmemit radio waves into space, and meansibnvar-ying a dimension of the-antenna'during the emission-oi. theradiowaves by the-antenna, thereby to-eflect modulation of the radio waves emitted by the antenna.

12; A radiotransmitter having, in combination, an antenna of thetypethat emits radio waves into space in response to electrical excitation by radio-frequencyenergy drawn-by-the antennafrom a radio-frcquency-energy-generating electricsystem prior-to-theemission of the radioirequency energy asradiowaves, an electric system for generating radio-frequency energy, means electrically connecting the antenna to the electric system in order that theantenna may draw' radio-trequency energy from the electric system, thereby to cause the antenna to emit radio waves into space, a mechanically vibratory-member, means'ior mechanically connecting the an tenna to the mechanically vibratory member to vary a dimension of the antenna mechanically in response to the mechanical vibrations of the mechanically'vibratory'member, thereby to effect modulation oi the radio waves-emitt'ed-by-theantenna.

13. In a radio-transmitter having an" antenna of the type that emits radio waves intospace in response to electrical excitation by radio-fre quency energy drawn by the antenna from a radio-frequency-energy-generating electric system prior to the emission of the radio-frequency energy as radio waves, a method'oi' the-character described that comprises ieeding-radio-irequency energy from the electric system in orderthat the antenna may draw radio-frequency energy'irom the electric system, thereby to cause the antenna to emit-radio waves into space, and'varying-a dimension oi the antenna during the'emissionoi the radio waves by the antenna in order-to eflect modulation of the radio waves emitted -bythe antenna.

14. An electromagnetic-system having; in combination, an electromagnetic-wave-reflectorfor reflecting a bundle oi rays of electromagnetic waves, a mechanically vibratory member, means for vibrating the mechanically vibratory member, and means mechanically connectingthe reflector to the mechanically vibratory member to transmit the mechanical vibrations from the mechanically vibratory member to and within the reriectcr, thereby to eflect modulation of the reflectedwaves.

15'. m a'radio transmitter having an antenna of the type that emits=radio=waves into-space in response to electrical excitation by radio-frequency energy drawnby the antenna from a radio-frequency-energy-generating electric system prior to the emission of the radio-frequency energy as radio waves, a method of the-character described that comprises-feeding radio-frequency energy from the electric system in order that the antenna may draw radio-frequency energy fromthe electric system, thereby to emit radio waves into space, and varying the length of the antenna during theemission of the radio waves-by the antenna in order to effect modul'ationoi the radio waves emitted by the antenna.

16. In a radio transmitter having an antenna oi the type that emits radio waves into" space in response to electrical excitation by radio-frequency energy drawn by the antenna from a radio-trequency-energy-generating electric system prior to the emission of the radio-frequency energy as radio waves, a method oithe character described that comprises feeding radio-irequency energy from the electric system in order that the antenna may draw radio-frequency energy from the electric system, thereby to emit radio waves into space, producing a signal, and varying a dimension of the antenna in accordance with the signal during the emission oftheradio waves by the antenna in orderv to. efl'ect the signal modulation of the rad o waves emitted by theantenna.

17. In a radio transmitter havingan antennaof the type that emits radio waves into space in response to electrical excitationby radio-frequency. enery drawn by the antenna from a radio-frequency-energy-generating electric system prior to the emission of the radio-frequency energy as radio \vavesand piezoelectric means, a method of the character described that comprises feeding radio-frequency energy from the electric system in order that the antenna may draw radio-frequency energy from' the electric system, thereby to emit radio waves into space, and varying a dimension of the antenna under the control. or

the piezoelectric meansduring the emission of the radio waves by the antenna in order to produce corresponding variations inthe energy drawn from the electric system by the antenna, thereby to'eflfect modulation of'the emitted radio waves.

18. In a radio transmitter having an antenna oi the type that emits radio: waves: into space in. response to electrical excitation by radio-irequency energy drawn by the antenna from a radio-irequency-energy-generating electric system prior to the emission oi the radio-frequency energy as radio waves and magnetostrictive means, a method of the character described that comprises feeding radio-frequency energy from the electric systemin order that the antenna may draw radio-frequencyenergy from the electric system, thereby to emit-radio waves into space, and varying a dimension of the antenna under the control'oi' the magnetostrictive means during the emission of the radio waves by the-antenna in order to produce corresponding variations in the energy drawn from the electric system by the antenna, thereby to eflect modulation of the emitted radio waves.

19. In a radiosystem having anantenna that receives radio waves from space, a method of the character described that comprises exciting the antenna toreoeive'radio-waves. and varyingrthe length of theantennaduring=the-z=eoaptibn or the radio waves by the antenna in order to effect modulation of the received radio waves.

20. In a radio system having an antenna of the type that emits radio waves into space in response to electrical excitation by radio-frequency energy drawn by the antenna from a radio-frequencyenergy-generating electric system prior to the emission of the radio-frequency energy as radio waves, a method of the character described that comprises exciting the antenna to emit radio waves, and .varying the effective impedance of the antenna during the emission of the radio waves by the antenna in order to efiect modulation of the emitted radio waves.

21. In a radio transmitter having a driven antenna and a parasitic antenna, the driven antenna being of the type that emits radio waves into space in response to electrical excitation by radio-frequency energy drawn by the driven antenna from a radio-frequency-energy-generat ing electric system, a method of the character described that comprises feeding radio-frequency energy from the electric system in order thatthe driven antenna may draw radio-frequency energy from the electric system, thereby to emit radio waves into space, positioning the parasitic antenna to intercept and re-radiate at least part oi the radio waves emitted by the driven antenna and varying a dimension of the parasitic antenna during the re-radiation of the radio waves by the parasitic antenna in order to effect modulation of the radio waves.

22. In a radio transmitter having an antenna and a conducting element spaced from but close to one end of the antenna to which it is electromagnetically coupled, the antenna being of the type that emits radio waves into space in response to electrical excitation by radio-frequency energy drawn by the antenna from a radio-frequency-energy-generating electric system prior to the emission of the radio-frequency energy as radio waves, a method of the character described that comprises feeding radio-frequency energy from the electric system in order that the antenna may draw radio-frequency energy from the electric system, thereby to emit radio waves into space,and varying the spacing and hence the degree of electromagnetic coupling between the conducting element and the said one end of the antenna during the emission of the radio waves by the antenna in order to effect modulation of the radio waves emitted by the antenna.

23. In a radio transmitter having an antenna and a conducting element electromagnetically coupled to a predetermined portion of the antenna, the antenna being of the type that emits radio waves into space in response to electrical excitation by radio-frequency energy drawn by the antenna from a radio-frequency-energy-generating electric system prior to the emission of the radio-frequency energy as radio waves, a method of the character described that comprises feeding radio-frequency energy from the electric system in order that the antenna may draw radiofrequency energy from the electric system, thereby to emit radio waves into space, producing a signal, and varying the degree of electromagnetic coupling between the conducting element and the said predetermined portion of the antenna in accordance with the signal during the emission of the radio waves by the antenna in order to effect signal modulation of the radio waves emitted by the antenna.

24. A radio transmitter having, in combination, an electric system for generating radio-frequency 8. energy,. an antenna electrically connected to the electric system in order that the antenna may draw radio-frequency energy therefrom to emit radio waves, and means for varying the length of the antenna during the emission of the radio waves to modulate the radio waves.

25. A radio system having, in combination, a generator 01 radio-frequency energy, a dipole element excited by the generator to emit radio waves, and means for varying a dimension of the dipole element during the emission oi the radio waves to modulate the radio waves.

26. A radio system having, in combination, an antenna 01' the type that may produce radio waves in space in response to electrical excitation by radio-frequency energy drawn by the antenna from a radio-frequency-energy-generating electric system prior to the production of the radioi'requency energy as radio waves, means for producing a signal, and means responsive to the signal-producing means for varying a dimension of the antenna in accordance with the signal during the production of the radio waves to signal modulate the radio waves.

27. A radio system having, in combination, an electric system for generating radio-frequency energy, an antenna of the type that emits radio waves into space in response to electrical excitation by radio-frequency energy drawn by the antenna from the radio-frequency-energy-generating electric system, means for enabling the antenna to draw radio-frequency energy from the electric system in order to emit radio waves into space, means for modulating the radio waves prior to their emission, a parasitic antenna positioned to intercept and re-radiate at least part of the emitted modulated radio waves, and means for varying a dimension of the parasitic antenna during the re-radia-tion of the radio waves, thereby further to modulate the re-radiated radio waves.

28. A radio system having, in combination, a linear antenna, means for exciting the antenna with radio-frequency energy, a conducting element spaced from but close to a predetermined portion near an end of the antenna to which it is electromagnetically coupled, and means for varying the spacing and hence the degree of electromagnetic coupling between the conducting element and the said predetermined portion of the antenna during the exciting of the antenna in order to eil'ect modulation of the radio frequency energy.

29. A radio transmitter having, in combination, a source of radio-frequency energy, an antenna excited from the source to draw radio-frequency energy therefrom in order to emit radio waves, and means for vibrating the antenna mechanically during the emission of the radio waves to cause the antenna to effect modulation of the emitted radio waves as an inherent response to its mechanical vibrations.

30. In a transmitter having an antenna for emitting a bundle of rays of radio waves, each ray along a predetermined direction, a method of modulating the radio waves that comprises varying a dimension of the antenna during the emission of the radio waves to vary a property of the radio waves, and retaining for each ray its predetermined direction.

31. A radio transmitter having, in combination, a source of radio-frequency energy, an omni-directional antenna excited from the source to emit radio waves in all directions, and a vibratory member to which the antenna is mechamcally 9 connected, vibrations of the member being adapted to modulate the radio waves.

32. A radio system having, in combination, a parasitic antenna for intercepting and reradiat- 8 radio waves, a conducting element electromagneticaily coupled to a predetermined portion of the antenna, means for producing a signal, and means controlled by the signal-producing means (or varying the degree or electromagnetic coupling between the conducting element and the parasitic antenna in accordance with the signal to signal modulate the re-radiated radio waves.

33. A radio system having, in combination, a linear parasitic antenna element (or intercepting and re-radiating radio waves, means for producing a signal, and means controlled by the signalproducing means for varying the length 01' the parasitic element in accordance with the signal to signal modulate the re-radiated radio waves.

34. In a radio system, a conducting element adapted to be disposed in an electromagnetic held in which there is an electromagnetic wave and of sumcient dimensions to permit of continuous electromagnetic interaction with the electromagnetic wave, and means for varying a dimension of the conducting element in accordance with a signal during the electromagnetic interaction with the electromagnetic wave in order to signalmodulate the electromagnetic wave.

35. An electric system having, in combination, a conducting element adapted continuously to support high-frequency current, and means for varying a dimension of the conducting element by subjecting it to mechanical vibrations to produce alternations oi the supported current in the conducting element of the same periodicity as the mechanical vibrations.

ROBERT H. RINES.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,763,220 Chromy June 10, 1930 1,966,446 Hayes July 17, 1934 2,001,132 Hanseii May 14, 1935 2,287,881 Holden June 30, 1942 2,368,174 Thomas et a1. Jan. 30, 1945 2,407,294 Shockley Sept. 10, 1946 2,409,462 Zworykin Oct. 15, 1946 2,412,631 Rice Dec. 17, 1946 2,432,984 Budenborn Dec. 23, 1947 2,461,005 Southworth Feb. 8, 1949 FOREIGN PATENTS Number Country Date 694,523 Germany Aug. 2, 1940 

